When an ECM of this kind operates at different temperatures with the same constant current, the torque generated by the motor changes as a function of the temperature of the rotor magnet. Depending on the temperature range in which the motor must operate, and depending on magnet temperature, changes in torque of up to 44% are possible in this context, i.e. at a constant motor current, the torque generated at a magnet temperature of +180° C. is 44% lower than at a magnet temperature of −40° C. Suitable temperature compensation is advisable in order to counteract such large changes in torque. For this purpose, the instantaneous temperature of the rotor magnet must be known (directly or indirectly) so that the torque can be appropriately compensated, as a function of that temperature.